/*
 * This program is free software: you can redistribute it and/or modify it under
 * the terms of the GNU General Public License as published by the Free Software
 * Foundation, either version 3 of the License, or (at your option) any later
 * version.
 *
 * This program is distributed in the hope that it will be useful, but WITHOUT
 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
 * FOR A PARTICULAR PURPOSE. See the GNU General Public License for more
 * details.
 *
 * You should have received a copy of the GNU General Public License along with
 * this program. If not, see <http://www.gnu.org/licenses/>.
 */
package net.sf.l2j.gameserver.model.zone.form;

import net.sf.l2j.gameserver.model.zone.L2ZoneForm;

/**
 * A not so primitive npoly zone
 * 
 * @author durgus
 */
public class ZoneNPoly extends L2ZoneForm {
	private int[] _x;
	private int[] _y;
	private int _z1;
	private int _z2;

	public ZoneNPoly(int[] x, int[] y, int z1, int z2) {
		_x = x;
		_y = y;
		_z1 = z1;
		_z2 = z2;
	}

	@Override
	public boolean isInsideZone(int x, int y, int z) {
		if (z < _z1 || z > _z2)
			return false;
		boolean inside = false;
		for (int i = 0, j = _x.length - 1; i < _x.length; j = i++)
			if ((_y[i] <= y && y < _y[j] || _y[j] <= y && y < _y[i])
					&& x < (_x[j] - _x[i]) * (y - _y[i]) / (_y[j] - _y[i])
							+ _x[i])
				inside = !inside;
		return inside;
	}

	@Override
	public boolean intersectsRectangle(int ax1, int ax2, int ay1, int ay2) {
		int tX, tY, uX, uY;
		// First check if a point of the polygon lies inside the rectangle
		if (_x[0] > ax1 && _x[0] < ax2 && _y[0] > ay1 && _y[0] < ay2)
			return true;
		// Or a point of the rectangle inside the polygon
		if (isInsideZone(ax1, ay1, (_z2 - 1)))
			return true;
		// If the first point wasn't inside the rectangle it might still have
		// any line crossing any side
		// of the rectangle
		// Check every possible line of the polygon for a collision with any of
		// the rectangles side
		for (int i = 0; i < _y.length; i++) {
			tX = _x[i];
			tY = _y[i];
			uX = _x[(i + 1) % _x.length];
			uY = _y[(i + 1) % _x.length];
			// Check if this line intersects any of the four sites of the
			// rectangle
			if (lineSegmentsIntersect(tX, tY, uX, uY, ax1, ay1, ax1, ay2))
				return true;
			if (lineSegmentsIntersect(tX, tY, uX, uY, ax1, ay1, ax2, ay1))
				return true;
			if (lineSegmentsIntersect(tX, tY, uX, uY, ax2, ay2, ax1, ay2))
				return true;
			if (lineSegmentsIntersect(tX, tY, uX, uY, ax2, ay2, ax2, ay1))
				return true;
		}
		return false;
	}

	@Override
	public double getDistanceToZone(int x, int y) {
		// Since we aren't given a z coordinate to test against
		// we just use the minimum z coordinate to prevent the
		// function from saying we aren't in the zone because
		// of a bad z coordinate.
		if (isInsideZone(x, y, _z1))
			return 0; // If you are inside the zone distance to zone is 0.
		double test, shortestDist = Math.pow(_x[0] - x, 2)
				+ Math.pow(_y[0] - y, 2);
		for (int i = 1; i < _y.length; i++) {
			test = Math.pow(_x[i] - x, 2) + Math.pow(_y[i] - y, 2);
			if (test < shortestDist)
				shortestDist = test;
		}
		return Math.sqrt(shortestDist);
	}

	/*
	 * getLowZ() / getHighZ() - These two functions were added to cope with the
	 * demand of the new fishing algorithms, wich are now able to correctly
	 * place the hook in the water, thanks to getHighZ(). getLowZ() was added,
	 * considering potential future modifications.
	 */
	@Override
	public int getLowZ() {
		return _z1;
	}

	@Override
	public int getHighZ() {
		return _z2;
	}
}
